main: add --poll-mode option

Add command line flag to disable automatic and adaptive micro sleep based on link speed and RX queue size. Signed-off-by: Robin Jarry <[email protected]>
DPDK · Apr 17, 2024 · 4ff2344 · 4ff2344
1 parent 712cf23
commit 4ff2344
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Showing 7 changed files with 55 additions and 35 deletions.
diff --git a/.clang-format b/.clang-format
@@ -90,7 +90,7 @@ IncludeBlocks: Regroup
 IncludeCategories:
   - Regex:           '^".*'
     Priority:        -1
-  - Regex:           '^<(br_|br/)'
+  - Regex:           '^<(br_|br\.)'
     Priority:        100
   - Regex:           '^<(rte_|event|ecoli|stb_|numa.h)'
     Priority:        500

diff --git a/main/br.h b/main/br.h
@@ -4,15 +4,15 @@
 #ifndef _BR
 #define _BR
 
-#include <event2/event.h>
-
-#include <sched.h>
 #include <stdbool.h>
 
-struct boring_router {
+struct br_args {
 	const char *api_sock_path;
 	unsigned log_level;
 	bool test_mode;
+	bool poll_mode;
 };
 
+const struct br_args *br_args(void);
+
 #endif
diff --git a/main/dpdk.c b/main/dpdk.c
@@ -19,7 +19,7 @@
 
 int br_rte_log_type;
 
-int dpdk_init(struct boring_router *br) {
+int dpdk_init(struct br_args *args) {
 	char main_lcore[32] = {0};
 	char **eal_args = NULL;
 	int ret = -1;
@@ -42,17 +42,17 @@ int dpdk_init(struct boring_router *br) {
 	arrpush(eal_args, "-a");
 	arrpush(eal_args, "0000:00:00.0");
 
-	if (br->test_mode) {
+	if (args->test_mode) {
 		arrpush(eal_args, "--no-shconf");
 		arrpush(eal_args, "--no-huge");
 		arrpush(eal_args, "-m");
 		arrpush(eal_args, "1024");
 	} else {
 		arrpush(eal_args, "--in-memory");
 	}
-	if (br->log_level >= RTE_LOG_DEBUG) {
+	if (args->log_level >= RTE_LOG_DEBUG) {
 		arrpush(eal_args, "--log-level=*:debug");
-	} else if (br->log_level >= RTE_LOG_INFO) {
+	} else if (args->log_level >= RTE_LOG_INFO) {
 		arrpush(eal_args, "--log-level=*:info");
 	} else {
 		arrpush(eal_args, "--log-level=*:notice");

diff --git a/main/dpdk.h b/main/dpdk.h
@@ -6,7 +6,7 @@
 
 #include "br.h"
 
-int dpdk_init(struct boring_router *);
+int dpdk_init(struct br_args *);
 void dpdk_fini(void);
 
 #endif
diff --git a/main/main.c b/main/main.c
@@ -37,41 +37,49 @@ static void usage(const char *prog) {
 	puts("  -h, --help                 Display this help message and exit.");
 	puts("  -v, --verbose              Increase verbosity.");
 	puts("  -t, --test-mode            Run in test mode (no hugepages).");
+	puts("  -p, --poll-mode            Disable automatic micro-sleep.");
 	puts("  -s PATH, --socket PATH     Path the control plane API socket.");
 	puts("                             Default: BR_SOCK_PATH from env or");
 	printf("                             %s).\n", BR_DEFAULT_SOCK_PATH);
 }
 
-static struct boring_router br;
-static struct event_base *ev_base;
+static struct br_args args;
+
+const struct br_args *br_args(void) {
+	return &args;
+}
 
 static int parse_args(int argc, char **argv) {
 	int c;
 
-#define FLAGS ":s:htv"
+#define FLAGS ":s:htpv"
 	static struct option long_options[] = {
 		{"socket", required_argument, NULL, 's'},
 		{"help", no_argument, NULL, 'h'},
 		{"test-mode", no_argument, NULL, 't'},
+		{"poll-mode", no_argument, NULL, 'p'},
 		{"verbose", no_argument, NULL, 'v'},
 		{0},
 	};
 
 	opterr = 0; // disable getopt default error reporting
 
-	br.api_sock_path = getenv("BR_SOCK_PATH");
-	br.log_level = RTE_LOG_NOTICE;
+	args.api_sock_path = getenv("BR_SOCK_PATH");
+	args.log_level = RTE_LOG_NOTICE;
 
 	while ((c = getopt_long(argc, argv, FLAGS, long_options, NULL)) != -1) {
 		switch (c) {
 		case 's':
-			br.api_sock_path = optarg;
+			args.api_sock_path = optarg;
 			break;
 		case 't':
-			br.test_mode = true;
+			args.test_mode = true;
+			break;
+		case 'p':
+			args.poll_mode = true;
 			break;
 		case 'v':
-			br.log_level++;
+			args.log_level++;
 			break;
 		case 'h':
 			usage(argv[0]);
@@ -94,8 +102,8 @@ static int parse_args(int argc, char **argv) {
 		return -1;
 	}
 
-	if (br.api_sock_path == NULL)
-		br.api_sock_path = BR_DEFAULT_SOCK_PATH;
+	if (args.api_sock_path == NULL)
+		args.api_sock_path = BR_DEFAULT_SOCK_PATH;
 
 	return 0;
 }
@@ -122,6 +130,8 @@ static ssize_t send_response(evutil_socket_t sock, struct br_api_response *resp)
 	return send(sock, resp, len, MSG_DONTWAIT | MSG_NOSIGNAL);
 }
 
+static struct event_base *ev_base;
+
 static void api_write_cb(evutil_socket_t sock, short what, void *priv) {
 	struct event *ev = event_base_get_running_event(ev_base);
 	struct br_api_response *resp = priv;
@@ -295,16 +305,16 @@ static int listen_api_socket(void) {
 	}
 
 	addr.un.sun_family = AF_UNIX;
-	strncpy(addr.un.sun_path, br.api_sock_path, sizeof addr.un.sun_path - 1);
+	strncpy(addr.un.sun_path, args.api_sock_path, sizeof addr.un.sun_path - 1);
 
 	if (bind(fd, &addr.a, sizeof(addr.un)) < 0) {
-		LOG(ERR, "bind: %s: %s", br.api_sock_path, strerror(errno));
+		LOG(ERR, "bind: %s: %s", args.api_sock_path, strerror(errno));
 		close(fd);
 		return -1;
 	}
 
 	if (listen(fd, BACKLOG) < 0) {
-		LOG(ERR, "listen: %s: %s", br.api_sock_path, strerror(errno));
+		LOG(ERR, "listen: %s: %s", args.api_sock_path, strerror(errno));
 		close(fd);
 		return -1;
 	}
@@ -318,11 +328,11 @@ static int listen_api_socket(void) {
 	);
 	if (ev_listen == NULL || event_add(ev_listen, NULL) < 0) {
 		close(fd);
-		LOG(ERR, "event_new: %s: %s", br.api_sock_path, strerror(errno));
+		LOG(ERR, "event_new: %s: %s", args.api_sock_path, strerror(errno));
 		return -1;
 	}
 
-	LOG(INFO, "listening on API socket %s", br.api_sock_path);
+	LOG(INFO, "listening on API socket %s", args.api_sock_path);
 
 	return 0;
 }
@@ -333,7 +343,7 @@ int main(int argc, char **argv) {
 	if (parse_args(argc, argv) < 0)
 		goto end;
 
-	if (dpdk_init(&br) < 0)
+	if (dpdk_init(&args) < 0)
 		goto dpdk_stop;
 
 	modules_init();
@@ -359,7 +369,7 @@ int main(int argc, char **argv) {
 		event_free_finalize(0, ev_listen, finalize_close_fd);
 	if (ev_base)
 		event_base_free(ev_base);
-	unlink(br.api_sock_path);
+	unlink(args.api_sock_path);
 	libevent_global_shutdown();
 	modules_fini();
 dpdk_stop:

diff --git a/modules/infra/control/graph.c b/modules/infra/control/graph.c
@@ -3,6 +3,7 @@
 
 #include "graph.h"
 
+#include <br.h>
 #include <br_api.h>
 #include <br_control.h>
 #include <br_datapath.h>
@@ -166,7 +167,10 @@ static int worker_graph_new(struct worker *worker, uint8_t index) {
 		goto err;
 	}
 	n_rxqs = 0;
-	max_sleep_us = 1000; // unreasonably long maximum (1ms)
+	if (br_args()->poll_mode)
+		max_sleep_us = 0;
+	else
+		max_sleep_us = 1000; // unreasonably long maximum (1ms)
 	arrforeach (qmap, worker->rxqs) {
 		if (!qmap->enabled)
 			continue;
@@ -177,10 +181,13 @@ static int worker_graph_new(struct worker *worker, uint8_t index) {
 		    qmap->queue_id);
 		rx->queues[n_rxqs].port_id = qmap->port_id;
 		rx->queues[n_rxqs].rxq_id = qmap->queue_id;
-		// divide buffer size by two to take into account the time to wakeup from sleep
-		rx_buffer_us = port_get_rxq_buffer_us(qmap->port_id, qmap->queue_id) / 2;
-		if (rx_buffer_us < max_sleep_us)
-			max_sleep_us = rx_buffer_us;
+		if (!br_args()->poll_mode) {
+			// divide buffer size by two to take into account
+			// the time to wakeup from sleep
+			rx_buffer_us = port_get_rxq_buffer_us(qmap->port_id, qmap->queue_id) / 2;
+			if (rx_buffer_us < max_sleep_us)
+				max_sleep_us = rx_buffer_us;
+		}
 		n_rxqs++;
 	}
 	rx->n_queues = n_rxqs;

diff --git a/modules/infra/datapath/main_loop.c b/modules/infra/datapath/main_loop.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2023 Robin Jarry
 
+#include <br.h>
 #include <br_control.h>
 #include <br_datapath.h>
 #include <br_log.h>
@@ -147,9 +148,11 @@ void *br_datapath_loop(void *priv) {
 		log(ERR, "pthread_setname_np: %s", rte_strerror(rte_errno));
 		return NULL;
 	}
-	if (prctl(PR_SET_TIMERSLACK, SLEEP_RESOLUTION_NS) < 0) {
-		log(ERR, "prctl(PR_SET_TIMERSLACK): %s", strerror(errno));
-		return NULL;
+	if (!br_args()->poll_mode) {
+		if (prctl(PR_SET_TIMERSLACK, SLEEP_RESOLUTION_NS) < 0) {
+			log(ERR, "prctl(PR_SET_TIMERSLACK): %s", strerror(errno));
+			return NULL;
+		}
 	}
 
 	log(INFO, "lcore_id = %d", w->lcore_id);